Diarylarsine manganese tetracarbonyl compounds



nited States Patent 3,tl80,4ii7 DIARYLARSENE MANGANESE TETRA- CARBQNYL (COMPOUNDS Rogers F. Lambert, Baker, La, assignor to Ethyl Corporation, New York, N.Y., a corporation of Virginia No Drawing. Filed Nov. 21, 196i Ser. No. 79,369 4- Claims. (Cl. 260-429) This invention relates to the discovery of novel diarylarsine manganese tetracarbonyl compounds and a method for their preparation.

A need exists in the art for thermally stable com pounds having a high content of arsenic and manganese in the molecule for use as extreme pressure (E.P.) additives in lubrication systems. The lubrication of rubbing systems which operate at extreme pressures presents unusual lubrication problems since the lubricant formed between the rubbing surfaces is subjected to high shear forces. Because of these high shear forces, the lubricant films which, under low pressure operating conditions, are present between the surfaces of the rubbing members are forced from between the rubbing surface-s so that effective lubrication is not obtained. In order to combat these problems accompanying extreme pressure conditions, it has been the practice heretofore to utilize lubricant addirtives which corrode the rubbing surfaces so as to form a film on the surface which, in itself, acts as a lubricant. A typical example of such an extreme pressure additive is carbon tetrachloride which breaks down in the lubricating system to form degradation products that react with the iron oxide coating on a ferrous rubbing member to form a film of ferrous chloride which acts to lubricate the rubbing metal surfaces. Since the lubrication mechanism of these additives involves corrosion of the rubbing members, these additives have no lubricating effect in rubbing systems in which the rubbing members have relatively non-reactive surfaces which resist corrosion by the additive. Typical examples of non-reactive surfaces are titanium on titanium, stainless steel on stainless steel and the like. Examples of non-metallic rubbing systems in which the rubbing members are non-responsive to extreme pressure additives are nylon, plastics, and the like.

-It has been discovered however that certain organemetallic compounds can be very effectively used to lubricate non-reactive surfaces as well as reactive surfaces even where such surfaces are under EP. conditions. Research work related to this discovery has indicated that manganese compounds and arsenic compounds are well suited for this lubrication usage because their degradartion products afford good lu ricity to the rubbing surfaces. Unfortunately, however, an appropriate compound having good thermal stability and having a high content of both manganese and arsenic has not been available up to this time.

Heretofore Hieber has reported the preparation of triphenylarsine manganese tetracarbonyl monomer, in Chem. Ber. 92, 1765-71 (1959) at page 1769. However, it is clear from this paper and the experimental work reported therein that triphenylarsine manganese tetracarbonyl monomer does not have good thermal stability properties. Furthermore, this compound has a lower content of manganese and of arsenic than is desirable for extreme pres sure lubrication. Therefore, the compound reported by Hieber does not fulfill the need for a manganese-arsenic compound having both high thermal stability and high contents of manganese and arsenic in the molecule.

It is therefore a general object of this invention to provide novel compounds which when used to lubricate rubbing systems under extreme pressure conditions form degradation products which effectively protect and lubricate the rubbing metal surfaces. It is a more particular 3,980,407 Patented Mar. 5, 1963 object of this invention to provide manganese-arsenic compounds having high thermal stability as well as high metal and metalloid contents. Other objects of this invention will be apparent from the following descriptions and claims.

The objects of this invention are accomplished by the discovery of diarylarsine manganese tetracarbonyl compounds having the formula Ar AsMn (CO 4 wherein Ar is an aryl hydrocarbon group containing up to about 18 carbon atoms. Particularly preferred compounds of this invention are diphenylarsine manganese tetracarbonyl, di(m-tolyl)arsine manganese tetracarbonyl and di(p-tolyl)arsine manganese tetracarbonyl because these are made from relatively inexpensive and readily available materials.

The compounds of this invention tend to exist for the most part as dimers although under some conditions they exhibit monomeric characteristics. For example, experiments have shown that diphenylarsine manganese tetracarbonyl and di(m-tolyl)arsine manganese tetracarbonyl exist both in solution and the solid state as dimers. On the other hand, di(p-tolyl)arsine manganese tetracarbonyl exists as a dimer in the solid state and as a monomer in solution.

Other typical examples of the compounds of this invenvention are di(2,4-xylyl)arsine manganese tetracarbonyl, di(2,5-xylyl) arsine manganese tetracarbonyl, di(3,5-xylyl) arsiue manganese tetracarbonyl, di(o-tolyl)arsine manganese tetracarbonyl, di(m-ethylphenyl)arsine manganese tetracanbonyl, di(p-tert-butylphenyl)arsine manganese tetracarbonyl, dicumenyl "arsine manganese tetracarbonyl, di-(2,4,6-trimethylphenyl)arsine manganese tetracarbonyl, di(alpha-naphthyl)arsine manganese tetracarbonyl, di (beta-naphthyDarsine manganese tetracarbonyl, phenylo-t-olyl arsine manganese tetracarbonyl, and the like.

The compounds of this invention are unique in that they are considerably more resistant to thermal decomposition than triarylarsine manganese compounds reported heretofore. By way of example, triphenylarsine manganese tetracarbonyl is indicated by Hieber to undergo some thermal decomposition at a temperature as low as C. In sharp contrast to this, various compounds of this invention have been found to be thermally stable to temperatures in excess of 230 C. Another feature of the compounds of this invention is that the manganese content can be as high as '14 percent while the arsenic content can be as high as 19 percent. Consequently, the compounds of this invention are admirably suited for use as lubricants for systems involved in extreme pressure service, such as hypoid gears, metal cutting machines, and the like.

The compounds of this invention are generally crystalline substances of various shades of yellow, and they are diamagnetic. It is interesting to note that the compound reported by Hieber is paramagnetic and is formulated on the basis of molecular weight to be exclusively monomeric.

Another embodiment of this invention is the process for producing diarylarsine manganese tetracarbonyl compounds comprising reacting a triarylarsine with manganese pentacarbonyl in an inert hydrocarbon solvent. accomplished by heating this mixture to a temperature sufficient to effect the desired reaction'i.e., to a tempera-i ture sufficiently high to cause the formation of the diaryl- 'arsine manganese tetracarbonyl. The preferred embodiments are the reactions of each of triphenylarsine, tri(m tolyl)arsine and tri(p tolyl)arsine with manganese pentacar bonyl where xylene is the inert .hydrocarbonsolvent.

A feature of this invention is the fact that incarrying out the above process the temperature of the reaction This is Q system must be maintained sufficiently high to cause the desired reaction to occur. However, the precise temperatures which are used are not susceptible of precise numerical delineation because the temperatures are determined primarily by the particular hydrocarbon solvent employed. For example, when triphenylarsine was reacted .with manganese pentacarbonyl in toluene, the desired reaction was effected at a temperature of 110 C. in other words, at this temperature diphenyiarsine manganese te-tracarbonyl was formed in 5 percent yield. But when Xylene was used as the solvent for this reaction, no detectable amount of the compound of the present invention was formed even though the reaction temperature was 120 C. Even infrared analysis failed to indicate the presence of the desired product in this reaction mixture. However, when triphenylarsine was reacted with manganese pentacarbonyl in xylene at 140 C. a 35 per cent yield of diphenylarsine manganese tetracarbonyl resulted. Consequently, When conducting the process of this invention care should be taken to use a temperature suflicient to elfect the formation of the diarylarsine manganese tetracarbonyl compound of this invention. Generally speaking,the minimum temperature at which this desired reaction will occur will fall somewhere in the range of about 100 C. up to about 140 C. depending upon the solvent used. At temperatures of about 140 C. the reaction proceeds at a rather rapid rate. The maximum temperature at which the process of this invention is conducted is largely dependent upon the nature of the reactants, the desired product, and the reaction solvent. Temperatures as high as about 220 C. or above can generally be used if desired.

The process of this invention will be more fully understood by reference to the following examples in which all parts are by weight.

Example I A solution of 3 parts of triphenylarsine and 2 parts of manganese carbonyl in parts of Xylene was heated at reflux temperature for 24 hours. On cooling of the solution a solid product separated which was removed by filtration and was purified by recrystallization from benzene. The product, diphenylarsine manganese tetracarbonyl which was a yellow solid, M.P. 255-260, was obtained in 35 percent yield.

Analysis.-Calcd. for C H MnAsOQ C, 48.5; H, 2.54; Mn, 13.9; As, 18.9; mol. wt., 792. Found: C, 48.4; H, 2.58; Mn, 14.0; As, 19.4; mol. wt., 773 (freezing point depression of naphthalene).

The diphenylarsine manganese tetracarbonyl had carbonyl absorption bands in the infrared carbonyl region at 4.89 microns, 5.02 microns, and 5.11 microns (CCL; solution).

Example 11 A solution of 2 parts of tri(m-tolyl)arsine and 1 part of manganese carbonyl in 11 parts of Xylene was heated at 138 for 4 hours. On cooling of the solution, di(mtolyl)arsine manganese tetracarbonyl separated as yellow crystals and was removed by filtration. The di(m-tolyl)- arsine manganese tetracarbonyl had a ME. 235240 and was obtained in 40 percent yield.

Analysis.-Calcd. for (C H ASMnOQ C, 51.1; H, 3.34; As, 17.7; Mn, 12.9; mol. wt, 848; Found: C, 51.3, 51.2; H, 3.40, 3.41; As, 19.9; Mn, 12.9 mol. wt., 799 (freezing point depression of naphthalene).

The di(m-tolyl)arsine manganese tetracarbonyl had infrared absorption bands in the carbonyl region at 4.87 microns, 5.02 microns and 5.12 microns (CCL; solution). The compound is diamagnetic.

Example III A solution of 1 part of tri(p-tolylarsine and 1 part of manganese carbonyl in 15 parts of Xylene was heated at reflux temperature for 7 hours. The solution was cooled and the di(p-tolyl)arsine manganese tetracarbonyl filtered and recrystallized from benzene. The. di(p-tolyi)arsine manganese tetracarbonyl, a yellow solid melting at 250-253, was obtained in 30 percent yield.

for (C18H14ASE&HO4)2I C, H, 3.34; As, 17.7; Mn, 12.9; C, 15.1; mol. wt, 848. Found: C, 52.3, 52.4; H, 3.46, 3.50; As, 17.2; Mn, 12.7; 0, 15.3; mol. wt., 424 (freezing point of depression of naphthalene).

The di(p-tolyl)arsine manganese tetracarbonyl was diamagnetic in the solid state and had infrared absorption bands in the carbonyl region at 4.87 microns. 5 microns and 5.12 microns (CCl solution).

Example IV A solution of 3 parts of triphenylarsin and 2 parts of manganese pentacaroonyl in 50 parts of toluene was heated at C. for 20 hours. The product recovered was diphenylarsine manganese tetracarbonyl. The yield of this product was 5 percent.

Example V A solution of 3 parts of triphenylarsine and 2 parts of manganese pentacarbonyl in 50 parts of decahydronaphtnalene was heated at a temperature of 194 C. for 20 hours. The product, diphenylarsine manganese tetracarbonyl, was obtained in a 25 percent yield.

Example VI A solution of 3 parts of triphenylarsine and 2 parts of manganese pentacarbonyl in 50 parts of 1,2,3,4-tetrahydronaphthalene was heated at a temperature of 140 C. for 18 hours. The product, diphenylarsine manganese tetracarbonyl, was recovered in an 8 percent yield.

As pointed out above there is a distinct interrelationship between the temperature at which the desired reaction occurs and the reaction solvents used. By way of example, where a solution of 3 parts of triphenylarsine was mixed with 2 parts of manganese pentacarbonyl in 50 parts of Xylene and the mixture was heated to a temperature of C. for 24 hours, no diphenylarsine manganese tetracarbonyl product was obtained. Furthermore, upon infrared analysis of the reaction mixture there was not detectable trace of diphenylarsine manganese tetracarbonyl.

The time of the reaction depends on the conditions under which the reaction is conducted, especially temperatures and solvents. However, times between a few minutes and several hours are generally quite adequate, although it is usually preferred to conduct the reaction for a period of from about 1 hour to about 24 hours.

The inert solvents used generally are hydrocarbons having a boiling point of at least about 100 C. The preferred solvents are aromatic, aliphatic or cycloaliphatic hydrocarbon compounds. The more preferred solvents are the cyclic hydrocarbon compounds since these have better solvency properties for the arsenic reactants used. Typical examples of solvents which can be used in this reaction are toluene, 1,2,3,4-tetrahydronaphthalene, decahydronaphthalene, cumene, diethylbenzene, Xylene, naphthalene, dirnethyl cyclohexane, nonane, decane, undecane, dodecane, aromatic naphthas, and the like. The most preferred solvents however are those which have a low freezing point (e.g., 0 C. or below) which simplifies the extraction of the reaction product.

The uses for the unique compounds of this invention are varied and many in number. As has been stated before, these arsine manganese compounds are important as lubricants in extreme pressure situations where small portions of the said compounds decompose at and between the contacting surfaces to lay down a surface of degradation products on the moving parts, thus permitting free movement of those parts. A special feature is that due to their high thermal stability, decomposition of these compounds occurs only at the point of extreme temperature and pressure thus permitting long use of the lubricant with these unique additives without premature thermal deterioration in the main body of the lubricant. In certain systems, e.g., sealed bearings, the compounds of this invention may be used in the absence of any other lubricant vehicle in order to efiect the desired lubrication. On the other hand, these compounds may be dissolved in mineral oil or synthetic lubricant bases to concentrations of even as low as a fraction of one percent by Weight in formulating extreme pressure lubricants for use in power transmission units, gear boxes, and the like. These compounds may also be used as anti-sludging agents in various types of oils such as transformer oils, glass annealing oils, and the like. Another use for these compounds is in the field of agriculture for use as herbicides, fungicides, and the like.

Having thus described the compositions of matter and the process for making them it is not intended that this invention be limited in any Way except as set forth in the following claims.

What is claimed is:

1. A diarylarsine manganese tetracarbonyl of the generic formula Ar AsMn(CO) 6 wherein Ar is an aryl hydrocarbon group containing from 6 to about 18 carbon atoms.

2. Diphenylarsine manganese tetracarbonyl. 3. Di(m-tolyl)arsine manganese tetracarbonyl. 4. Di(p-tolyl)arsine manganese tetracarbonyl.

References Cited in the file of this patent UNITED STATES PATENTS Coflield et al Sept. 1, 1959 FOREIGN PATENTS 606,876 Canada Oct. 18, 1960 OTHER REFERENCES Hieber et al.: Chem. Ber. 92, No. 8, 1765-71 (1959).

Proceedings of the Chem. 506., (Nov. 1957), pp. 321- 322.

J.A.C.S., vol. 81, No. 9, May 5, 1959, pp. 2273 to 2274.

Journal of the Chem. 800., July 1959, pp. 2323 to 2327. 

1. A DIARYLARSINE MANGANESE TETRACARBONYL OF THE GENERIC FORMULA 